FR2877412A1 - Spiral spring for steering wheel with fixed common control of steering assembly of motor vehicle, has electrical sheath constituted by strand of electric cables, and including U shaped profile that is fixed by fitting on coil field - Google Patents

Abstract

The spring has an electrical sheath constituted by a strand (20) of electric cables. The sheath has a U shaped profile (23) that is fixed by fitting on a field of a coil (10). The profile is held on the coil by sticking the strand on the field of the coil. The cables transmit control of certain functions such as speed control or navigation, of a vehicle from a steering wheel to corresponding units.

Description

The present invention relates to a spiral spring of a steering wheel

stationary plants.

  The invention finds a particularly advantageous application in the field of producing spiral springs intended in particular for the steering assemblies of motor vehicles.

  In the automotive industry, a new concept, known as a flywheel with fixed central controls, is emerging today in terms of vehicle steering assemblies. This is to make fixed a central hub adjacent to the steering wheel, that is to say free to rotate relative to the steering wheel, so that it can receive a number of functions controls such as radio, air conditioner , navigation, cruise control, ..., the purpose of this steering wheel concept with fixed central controls being to facilitate access to these functions by commands located directly on the steering wheel of the vehicle.

  For this purpose, it uses a mechanical architecture based on the use of a coil spring, also called spiral spring, to maintain the position of the steering wheel and the steering mechanism unchanged, while integrating the transmission and electrical cables. without making any changes to the basic configuration of the vehicle.

  The spiral spring used to immobilize the central part of the steering wheel, or hub, is directly fixed on the sheath of the steering column and on the safety cushion. It must be very stiff in axial torsion and very flexible in axial compression.

  In this perspective, a solution adopted consists in producing a spring with flat turns. "Flat coil" means a turn whose thickness, that is to say the dimension in the direction of the axis of the turns, is much smaller than the height, that is to say the dimension in a direction perpendicular to the axis, in a ratio of 1/5, or even less than 1/20.

  The invention is more particularly in this context of spring with flat turns.

  A problem that arises in the integration of steering assemblies based on the concept of a flywheel with fixed central controls is to carry out the passage, through the retained architecture of the spiral spring, of the electric transmission cables connecting the controls placed at the steering wheel of the vehicle to the bodies responsible for performing the corresponding functions.

  A solution to this technical problem consists, according to the present invention, in a spiral spring fixed hub flywheel, remarkable in that it comprises an electrical sheath attached to said spiral by fastening means at least partially carried by said electrical sheath .

  Thus, one obtains an implementation of the electric cables integrated in the spiral spring of the flywheel with fixed central controls, which considerably reduces the bulk of the assembly. On the other hand, the fastening means being carried at least in part by the cable sheath itself, it is possible to limit, or even to avoid, any sensitive mechanical modifications of the spiral spring.

  According to a first implementation of the invention, said electrical sheath is formed by a strand of electrical cables, whereas, in a second implementation, said electrical sheath consists of a sheet of electrical cables.

  In this context of electric cables enclosed in a strand or a layer of conductors, one can provide several embodiments of the spiral spring according to the invention.

  In a first embodiment, said electrical sheath is glued to one end of said spiral.

  In a second embodiment, said electrical sheath comprises a section adapted to be fixed by fitting on a field of said spiral.

  In a third embodiment, said electrical sheath has a staple tab adapted to cooperate with a staple tab conjugate said spiral.

  In a fourth embodiment, said electrical sheath comprises clipping means, also referred to as latching means on said spiral.

  In a fifth embodiment, said electrical sheath has hot riveting means on said spiral.

  Furthermore, the invention also provides that said electrical sheath is constituted by a flexible printed circuit.

  In this case, according to a first embodiment, said flexible printed circuit is a spiral circuit bonded to a wall of the spring coil.

  According to a second embodiment, said flexible printed circuit is a folded circuit glued to the walls of said spiral.

  The following description with reference to the accompanying drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be achieved.

  Figure la is a sectional view of a first embodiment of the invention by gluing a strand of cables.

  Figure lb is a sectional view of a second embodiment of the invention by gluing a strand of cables.

  Figure 2a is a sectional view of a first embodiment of the invention by gluing a sheet of cables.

  Figure 2b is a sectional view of a second embodiment of the invention by gluing a sheet of cables.

  Figure 3 is a sectional view of an embodiment of the invention by fitting a cable strand.

  Figure 4a a sectional view of an embodiment of the invention by fitting a sheet of cables.

  Figure 4b is a variant of the embodiment of Figure 4a.

  FIG. 5 is a first variant of the embodiment of FIG.

  FIG. 6 is a second variant of the embodiment of FIG.

  Figures 7a and 7b are side views of the alternative embodiment of Figure 6 before and after bending.

  FIG. 8 is a third variant of the embodiment of FIG.

  FIG. 9 is a perspective view of the variant embodiment of FIG. 8.

  Figure 10a is a sectional view of a first embodiment of the invention by stapling a cable strand.

  Fig. 10b is a perspective view of a spiral edge shaped according to the embodiment of Fig. 10a.

  Figure 11a is a variant of the embodiment of Figure 10a.

  Figure 11b is a perspective view of a coil edge shaped according to the embodiment of Figure 11a.

  Figure 12a is a sectional view of a first embodiment of the invention by stapling a sheet of cables.

  Figure 12b is a perspective view of a coil edge shaped according to the embodiment of Figure 12a.

  Figure 13a a sectional view of a second embodiment of the invention by stapling a cable strand.

  Figure 13b a variant of the embodiment of Figure 13a.

  Fig. 14 is a sectional view of a third embodiment of the invention by stapling a strand of cables.

  Figure 15 is a sectional view of a second embodiment of the invention by stapling a cable ply.

  Figures 16, 17 and 18 are sectional views of three embodiments of the invention by clipping, or snap, a cable strand.

  Fig. 19 is a sectional view of an embodiment of the invention by hot riveting a cable strand.

  Figure 20 is a sectional view of an embodiment of the invention by hot riveting a cable ply.

  Figure 21 is a top view of a printed circuit for bonding to a wall of a spiral spring according to the invention.

  FIG. 22a is a top view of a printed circuit intended to be folded and glued to the walls of a spiral spring according to the invention.

  Figure 22b is a top view of the printed circuit of Figure 22a partially bent.

  FIG. 23 is a sectional view of the printed circuit of FIGS. 22a and 22b folded and glued to the walls of a spiral spring according to the invention.

  In Figure la is shown an end of a spiral 10 of a flywheel spring fixed hub. An electrical sheath, constituted in this example by a strand 20 of electric cables 21, is fixed on the field of the spiral 10 by gluing made by a glue deposit 11 at the interface between the strand 20 and the spiral 10. Remember that the cables 21 are intended to transmit the control of certain functions of the vehicle, such as radio, air conditioner, navigation, speed control, ..., from the steering wheel to the corresponding organs.

  In the embodiment of Figure la, the bonding is performed on the outer field of the spiral 10. It is understood that this bonding could just as well be performed on the inner field of the spiral. This remark also applies to all other embodiments of the invention which will be described later in this memoir.

  FIG. 2a shows a variant of FIG. 1 in which the electrical sheath is constituted by a sheet 20 'of cables 21. In this case, the sheet 20' is glued to one end of the spiral, in the vicinity of the external field.

  In order to ensure a better hold of the electrical sheath on the spiral 10, it is provided, as shown in Figures lb and 2b, that the strand 20 or the web 20 'has a tab 22, 22' of gluing.

  In the embodiments shown in Figures 3 to 9, the electrical cable sheath has a U-shaped section adapted to be fixed by fitting on a field of the spiral 10, the outer field in the examples shown in these figures.

  More specifically, Figures 3, 4a and 4b refer to a simple fitting of the section 23 of the strand 20 (Figure 3) and the profiles 23 ', 23 "of the plies 20', 20" (Figures 4a and 4b). The plies 20 'and 20 "are differentiated by the distribution of the cables between the two branches of the U-shaped profiles 23' and 23".

  FIG. 5 illustrates a first variant of the embodiment of FIG. 3 in which the profile 23 is held on the spiral 10 by bonding the strand 20 to the field of the spiral 10.

  In situations where the radius of curvature of the spiral 10 is small, it is advantageous to be able to easily bend the U-shaped section along the edge of said spiral. For this purpose, Figure 6 shows an embodiment where the profile of the strand 20, for example, has slits 231 bending. It is possible to see in FIGS. 7a and 7b in side view the shape of the profile 23 before and after bending.

  Finally, the simple fitting of the U-shaped section can be advantageously completed by a pinching force, so as to favor its retention on the spiral 10. This pinching force is obtained, in accordance with FIG. 8, by means of a reinforcement 24 holding a perspective view is given in Figure 9.

  Figures 10a to 15 relate to the attachment of the electrical sheath to the spiral 10 by stapling.

  Figures 10a to 12b relate to embodiments where a strand 20 and a web 20 'are directly stapled on a spiral 10 consisting of a single sheet. FIGS. 10b, 11b and 12b show in perspective views how the spiral sheet 10 must be shaped on one of its edges to make the fastening clips of the strand 20 and the ply 20 'respectively corresponding to FIGS. 10a, 11a and 12a.

  In FIGS. 14 and 15, the spiral is also made in a single plate, but the stapling is obtained by means of a tab 25, 25 'of stapling respectively arranged on the strand and on the sheet, said tab of FIG. stapling cooperating with a conjugate lug arranged on the spiral 10.

  Figure 13a shows how a strand 20 can be stapled on a spiral 10 formed of two assembled sheets. In a variant illustrated in Figure 13b, the strand 20 is inserted into a housing of a spiral 10 formed of a folded sheet on itself.

  Figures 16 to 18 relate to fastening means by clipping a strand 20 on a spiral 10.

  In Figure 16, the attachment is made by a metal clip 26. The clip 27 of Figure 17 is of the plastic clip type, while that of Figure 18 is a plastic clip 28 hot riveted.

  As shown in FIGS. 19 and 20, the strand 20 and the ply 20 'can be attached to the spiral 10 by riveting a tab, referenced 29 in FIG. 19, by means of a hot-deformed plastic rivet. The equivalent in Figure 20 of the tongue 29 of Figure 19 is constituted by the body of the web 20 '.

  The electrical sheath enclosing the electrical transmission conductors functions can also be obtained in the form of a flexible printed circuit.

  FIG. 21 shows such a circuit in the form of a spiral similar to the spiral of the fixed hub flywheel spring, the attachment of this circuit being made by gluing on one face of the spiral.

  It is possible to fix a flexible printed circuit on both sides of a spiral by giving to said circuit the shape shown in FIG. 22a. This shape is obtained from an initially flat film cut by press stamping.

  As can be seen in FIG. 22b, a folding around the dotted axis of FIG. 22a, followed by a gluing, leads the structure shown in the section of FIG. 23 where the circuit 201 "surrounds the end of the spiral 10 on either side of the field Successive folds around the axes equivalent to that of Figure 22a are performed in order to complete the constitution of the spiral spring equipped with the flexible printed circuit.

Claims (15)

  1. spiral flywheel spring with fixed central controls, characterized in that it comprises an electrical sheath (20, 20 ', 20 ", 201") fixed to said spiral (10) by fixing means at least partially carried by said electrical sheath.   2. Spring according to claim 1, characterized in that said electrical sheath is constituted by a strand (20) of electric cables.   3. Spring according to claim 1, characterized in that said electrical sheath consists of a web (20 ', 20 ") of electric cables.   4. Spring according to one of claims 2 or 3,   characterized in that said electrical sheath (20, 20 ') is glued to one end of said spiral (10).   5. Spring according to claim 4, characterized in that said electrical sheath (20, 20 ') comprises a tongue (22, 22') for bonding.   6. Spring according to one of claims 2 or 3, characterized in that said electrical sheath (20, 20 ', 20 ") comprises a profile (23, 23', 23") adapted to be fixed by fitting on a field said spiral (10).   7. Spring according to claim 6, characterized in that said profile (23) has transverse slots (231) for bending.   8. Spring according to one of claims 6 or 7, characterized in that said profile (23) comprises a frame (24) for holding.   9. Spring according to any one of claims 6 to 8, characterized in that said profile (23) is bonded to said spiral (10).   10. Spring according to one of claims 2 or 3,   characterized in that said electrical sheath (20, 20 ') has a tab (25, 25') of stapling adapted to cooperate with a lug (15) of staple conjugate said spiral (10).   11. Spring according to one of claims 2 or 3,   characterized in that said electrical sheath (20) comprises means (26, 27, 28) latching on said spiral (10).   12. Spring according to one of claims 2 or 3, characterized in that said electrical sheath (20, 20 ') comprises means (29) hot riveting said spiral (10).   13. Spring according to claim 1, characterized in that said electrical sheath is constituted by a flexible printed circuit (20 "').   14. Spring according to claim 13, characterized in that said flexible printed circuit is a spiral circuit bonded to a wall of the spiral spring (10).   15. Spring according to claim 13, characterized in that said flexible printed circuit (20 '") is a folded circuit glued on the walls of said spiral (10).